Capacity in wireless communication networks is generally limited by the radio spectrum available. The capacity of a wireless communication network, therefore, depends on efficient use of the available radio spectrum. Since the radio spectrum allocated to a wireless cellular network is often fixed and because network operators generally desire increase capacity, there are efforts to make more efficient use of the allocated radio spectrum.
In a wireless cellular network, the allocated radio spectrum is often divided, for example, by time, frequency, and/or space. For instance, the allocated radio spectrum may be divided into a subset of frequency channels. The frequency channels are usually spaced far enough apart so that they do not overlap and generate cross-channel interference. In this regard, each of these channels may be used independently of one another since they use a separate frequency range. In a wireless cellular network, some channels may be dedicated to downlink communication and other channels may be dedicated to uplink communication.
Radio spectrum may also be divided by time and/or space. An uplink channel, for instance, may be divided into distinct time slots. Each user equipment (UE) in the wireless cellular network may be assigned a time slot in which the UE is granted the right to transmit data on the uplink channel. In this sense, the radio spectrum is said to be time divided. Radio spectrum may also be divided by space by reusing, for example, frequencies in disparate locations. For instance, a plurality of cells in the wireless cellular network may cover non-overlapping areas such that a given frequency may be reused across the plurality of cells without experiencing interference on the given frequency.